It is made by Aluminum CNC.
Bike bicycle Aluminum Standard Handlebar Mount 31.8mm fit for Gopro Hero 2 / 3.
Shape: round 30mm -31.8mm

This item is made by Aluminum.
Bike aluminum Handlebar Bar Mount Adapter fits for GoPro Hero 3 / Hero 2
Dimension: 135*79*56 (MM)

Attach your GoPro camera to handlebars, seatposts, ski poles and more.
max for 4cm diameter tubes.
You can also clamp to chain stay, small roll bars, bolt-heads, and kitesurfing control bars, or even use to create a handheld boom ¨C any pole that is in the size range above.

Whether you like surfing waves or pow, affix the Surf Mount to your board of choice and then show the world what you can do.
Surf mount adheres to board and stands up to water, waves, nicks and dings Safety leash tethers your camera’s waterproof housing to the mount to provide additional peace of mind.
Material: plastic

Delivers versatile camera-angle adjustability to capture a wide range of perspectives
Can be attached to any GoPro mount that features a quick release base
Doubles as an adjustable handheld camera grip